The present invention relates to a soundboard system for a stringed musical instrument and to stringed musical instruments having such a soundboard system. The invention has particular application where the stringed musical instrument is a guitar, though the invention has application to any stringed musical instrument.
A stringed musical instrument typically has multiple strings strung at high tension from a nut to a bridge. Such an instrument has a single soundboard, typically with at least one sound hole. In a flat-top stringed musical instrument, such as a guitar, the high tension force of the strings constantly tends to pull the sound board up off of the instrument. In an arch-top stringed musical instrument, such as a violin, the high tension force of the strings constantly tends to push the soundboard down toward the back of the instrument. This force tends to cause the soundboard to bend, crack, or otherwise break or distort.
It is desirable to achieve greater sound volume from a stringed musical instrument. It is also desirable to achieve better tone quality from a stringed musical instrument, such as by producing sound that has a more complex texture or richer bass. To increase the sound volume, strings of a heavier gauge can be used. However, the use of heavier gauge strings increases the force on the soundboard, thus increasing the tendency for the string tension to cause the soundboard to break or distort.
The use of internal bracing on the underside of the soundboard is one way in which prior art designs have attempted to improve the strength and durability of the soundboard. For example, the following patents disclose different internal bracing patterns or structures for stringed musical instruments: U.S. Pat. No. 6,166,308 issued to Lam; U.S. Pat. No. 5,952,592 issued to Teel; U.S. Pat. No. 5,469,770 issued to Taylor; and U.S. Pat. No. 5,461,958 issued to Dresdner et al. However, the use of internal bracing can negatively affect tone quality. To reduce this negative effect on tone quality, bracing patterns may be complex and, thus, difficult and expensive to design and manufacture.
Another way in which prior art designs have attempted to improve the strength and durability of the soundboard is by making the soundboard of a non-conventional material. For example, U.S. Pat. No. 6,107,552 issued to Coomar et al. discloses a soundboard made from a composite structure with two layers of a stiffened graphite sheet material, with a low-density core material interposed between the two layers. The use of such a material may reduce the need for internal bracing. However, such a material may be expensive and time consuming to manufacture, and its use could adversely affect tone quality.
It is also desirable for a stringed musical instrument to allow the use of strings having different string action (i.e., string height). Different musicians may prefer to use strings having different action, based on personal preference. Different types of music also may lend themselves to strings having different action. In general, if the string action is too high, fingering may become difficult. If the string action is too low, the strings may buzz undesirably against frets on the finger board.
Prior art designs typically do not allow a musician to easily adjust the string action. Such adjustments typically cannot be made xe2x80x9con the fly.xe2x80x9d To lower the string action, it is typically necessary to shave or sand a saddle of the bridge. To raise the string action, it is typically necessary to shim the saddle. These adjustments typically must be done by a professional luthier and may be expensive and inconvenient.
The present invention is directed to a stringed musical instrument. In one embodiment of the invention, the stringed musical instrument is a guitar, having two soundboards. A bridge is located between the two soundboards. The two soundboards tend to equalize any upward or downward pull by the bridge caused by the tension of the strings, thus lessening the tendency of the soundboard to bend, crack, or otherwise break or distort. This embodiment of the invention allows the use of heavier gauge strings and higher string tension to produce a greater sound volume. This embodiment of the invention also reduces the need for internal bracing on the underside of the soundboards. This embodiment of the invention also allows the instrument to be constructed from conventional materials using conventional methods of construction.
In an embodiment of the invention, it is not necessary for either soundboard to have a traditional sound hole. Instead, the two soundboards of the invention may be structured such that they form an internal J-baffle. The J-baffle gives the instrument an improved tone quality, allowing it to produce sound having a more complex texture and richer bass.
An embodiment of the invention may allow for the bridge to be easily removed. The bridge may then be easily replaced with a replacement bridge that allows the use of strings having a different action. This removable and replaceable bridge allows a musician to change string action xe2x80x9con the fly,xe2x80x9d without the need for expensive and inconvenient professional adjustment.
An embodiment of the invention may also include an arm cutout. A right-handed player of a stringed musical instrument such as a guitar typically uses the point where his or her right arm touches the front of the instrument as a reference point to the strings. Similarly, a left-handed player typically uses the point where his or her left arm touches the front of the instrument as a reference point to the strings. The arm cutout maintains the same arm/string relationship as with traditional instruments. Both right-handed and left-handed embodiments having arm cutouts are possible.